I apologize for doing this to you; but, I'm immediately going to refer you to my new blog ("IdeaRoom3D") that will focus on using M3D 3D printers and materials with an emphasis on classroom applications and creating crafts. If you have been following this blog, it might be useful to you to also follow the new blog.
I am starting a new series that will explore using Craftwell's eBrush airbrush system that primarily uses alcohol markers instead of traditional ink. The goal is to use colorization to add value to the things we print.
While certainly not perfect, both the process (entirely enjoyable) and the results (better than expected) have convinced me that this system is perfect for 3D printing owners. It's relatively easy to use, affordable and applies color quite well to both flexible and hard 3D printing materials. I will also be testing it with the Z450 powder printer. We have found that consumer 3D scanners use relatively low resolution color images so it is worth exploring coloring people scans with an airbrush system.
At any rate.take a look at my first try. The article, with an image, can be found at this LINK.